1. Field of the Invention
The present invention relates to a computing circuit for an electronic taxi fare meter which computes the tariff travel distance as well as the tariff travel time of a taxi.
2. Description of the Prior Art
Taxi fare meters heretofore known in the art are entirely of the mechanical type which employ a gear and cam mechanism and in which the premium fare mechanism effects the calculation of the premium fares on the distance of trips by properly changing the number of teeth in the gears, but there is no means for the calculation of premium fares on the travel times. Therefore, the disadvantages of these conventional meters are possibility of errors in the measurement of the distance of trips due to the wear of the gears in service, danger of malfunctions due to any improper engagement of the gears, and the absence of any suitable mechanical means for the calculation of premium fares on the time rate basis.
Another disadvantage is that where the basic distance and the fixed unit distance subsequent to the basic distance (hereinafter referred to as a fixed additional distance) differ for different business areas of taxis or for different classes of taxis, cumbersome procedures are required such as the adjustment of the gears in the taxi fare meter, the changing of fare indicating plates, etc.
Still another disadvantage of the conventional taxi fare meters is that the switching from the distance rate system to the time rate system takes place when the speed of a taxi drops below a predetermined threshold speed, and therefore malfunctions tend to occur in the vicinity of the threshold speed, thus giving rise to problems from the standpoint of accuracy.